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Results for “Restrictive”

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At least 667 records · Page 37Linked to original sources

PubMed2004

Increased hypothalamic melanin concentrating hormone gene expression during energy restriction involves a melanocortin-independent, estrogen-sensitive mechanism.

Increased expression of melanin concentrating hormone (MCH), an orexigenic neuropeptide produced by neurons in the lateral hypothalamic area (LHA), is implicated in the effect of energy restriction to increase food intake. Since melanocortins inhibit Mch gene expression, this effect of energy restriction to increase Mch signaling may involve reduced hypothalamic melanocortin signaling. Consistent with this hypothesis, we detected increased hypothalamic Mch mRNA levels in agouti (Ay) mice (by 102%; P < 0.05), a model of genetic obesity resulting from impaired melanocortin signaling, compared to wild-type controls. If reduced melanocortin signaling mediates the effect of energy restriction, hypothalamic Mch gene expression in Ay mice should not be increased further by energy restriction, since melanocortin signaling is impaired in these animals regardless of nutritional state. We therefore investigated the effects of energy restriction on hypothalamic Mch gene expression in both Ay mice and in wild-type mice with diet-induced obesity (DIO). Responses in these mice were compared to those induced by administration of 17beta-estradiol (E2) at a dose previously shown to reduce food intake and Mch expression in rats. In both Ay and DIO mice, energy restriction increased hypothalamic Mch mRNA levels (P < 0.05 for each) via a mechanism that was fully blocked by E2. However, E2 did not lower levels of Mch mRNA below basal values in Ay mice, whereas it did so in DIO mice. Thus, the effect of energy restriction to increase hypothalamic Mch gene expression involves an E2-sensitive mechanism that is not altered by impaired melanocortin signaling. By comparison, impaired melanocortin signaling increases hypothalamic Mch gene expression via a mechanism that is insensitive to E2. These findings suggest that while both energy restriction and reduced melanocortin signaling stimulate hypothalamic Mch gene expression, they do so via distinct mechanisms.

Animals↗

PubMed2005

Behaviour of food restricted broilers during rearing and lay--effects of an alternative feeding method.

Broiler breeders are subjected to quantitative food restriction in order to control their growth, and this restriction is particularly severe during rearing. While such restriction improves some welfare problems associated with ad libitum feeding, it causes others: birds routinely show abnormal oral behaviours and have elevated plasma corticosterone concentration (PCC) and changes in white blood cell counts (WBCs). The aim of this study was to examine if feeding birds qualitatively restricted diets ad libitum during rearing could reduce signs of impaired welfare, as judged by behaviour and blood indices of stress, while also meeting commercially desired growth rates and uniformity. Furthermore, we examined what carry-over effects such a feeding method had on birds in the laying phase when all birds were fed on a conventional quantitative restriction regime. During rearing (1-20 weeks of age), pens of birds were either fed limited amounts of standard basal diets (Control, i.e. quantitative restriction), or ad libitum diets consisting of standard basal diets with gradually increasing levels of calcium propionate (CaP) and a constant level of oat hulls (OH), designated CaP+OH (i.e. qualitative restriction). Results showed that, during rearing, weights and weight uniformity were similar for the two groups. During feeding motivation tests, Control birds always consumed more food than CaP+OH birds. This suggests that Control birds were more highly motivated to feed than CaP+OH birds, although care has to be taken in interpreting these results. Treatment did not affect PCCs or WBCs, but there was a general decline in PCCs with bird age. All reported behaviours differed significantly between treatment groups during rearing, but disappeared during lay when all birds were fed a similar amount of food. Control birds spent up to 50% of time in object pecking during rearing periods, but this behaviour was virtually non-existent in birds in the qualitative feeding regime. Overall, the results indicate that broiler breeders can be successfully limited in growth rates by qualitative food restriction and this results in significant changes of behaviour that suggest improvements to bird welfare.

Age Factors↗

PubMed2006

H. saimiri tyrosine-kinase interacting protein inhibits Tat function: a prototypic strategy for restricting HIV-1-induced cytopathic effects in immune cells.

Herpesvirus saimiri (HVS)-transformed human T cells become permissive for X4 and R5 strains of human immunodeficiency virus type 1 (HIV-1), evidence that HVS-encoded proteins associated with T cell transformation enhance HIV-1 replication. Analyzing the contribution of transformation-associated bicistronic HVS open reading frames (ORF) to HIV-1 replication revealed expression of the second ORF saimiri transformation-associated protein type C (StpC) conferred the permissive phenotype to T cells. In contrast, expression of the first HVS ORF tyrosine-kinase interacting protein (Tip) in the absence of StpC enhanced restriction of HIV-1 replication in T cell lines and peripheral blood mononuclear cells. Understanding the mechanism whereby Tip enhanced restriction of HIV-1 replication may uncover unique pathways that could be targeted therapeutically. Here we report that Tip restricts HIV-1 replication in a monocyte-derived cell line and restricts reactivation of replication of HIV-1 in a T cell line harboring provirus. In this report, we begin to unravel the molecular underpinnings of Tip-mediated restriction. Tip mediates both lymphocyte-cell-specific kinase (Lck)-dependent and -independent effects on HIV-1 replication. We also provide evidence that Tip-mediated restriction is in part due to inhibition of Tat transactivation of the HIV-1 long terminal repeat (LTR). Expression of Tip in T cells increased activation of Stat1 and Stat3, as well as activation of protein kinase RNA-dependent (PKR/p68) and interferon-gamma production. Taken together, these results provide evidence that Tip restricts HIV-1 replication and reactivation by inhibiting HIV-1 transcription while inducing an intercellular antiviral state. We propose that genetically engineered vectors driving Tip expression could provide a prototypic strategy for restricting HIV-1 replication and reactivation in diverse cell lineages.

Cell Line↗

PubMed2006

Moderate calorie restriction improves cardiac remodeling and diastolic dysfunction in the Dahl-SS rat.

Caloric restriction extends longevity and reduces the onset of chronic disease in many animal models. Recently, caloric restriction was shown in humans to be associated with lower blood pressure, decreased systemic inflammation, and improved cardiac diastolic parameters. However, the causation and mechanisms of caloric restriction were obscured by the varied diet composition of the participants. The Dahl salt-sensitive rat which develops gradual, hypertension-associated diastolic dysfunction was used in this study to assess the impact of caloric restriction upon decompensated pressure-overload hypertrophy. Male Dahl salt-sensitive rats were provided either a low-salt diet or a high-salt diet to initiate heart failure progression. A further subset of high-salt rats underwent 15% calorie restriction, with salt load held constant. Parameters measured included serial systolic blood pressure, body weight, and changes of left ventricular systolic and diastolic parameters and ventricular geometry by echocardiography. After 18 weeks, fasting glucose, blood lipids, heart weight, kidney weight, lung weight, plasma interleukin-6 and TNF-alpha, and cardiac lipid peroxidation were measured. Low-salt rats did not develop heart failure. While high-salt rats displayed features of decompensated pressure-overload hypertrophy, moderate calorie restriction remarkably reduced morbidity. Compared to the high-salt fed group, the high-salt, calorie-restricted group showed reduced blood pressure, delayed onset of cachexia, lower fasting hyperlipidemia, lower cardiac, renal and lung weight, less plasma IL-6 and TNF-alpha, less cardiac oxidative damage, and improved diastolic chamber function and cardiac index. Modest calorie restriction, independent of salt intake, reduced pathogenesis in this well described model of decompensated pressure-overload hypertrophy.

Animals↗

PubMed2000

Parents' restrictive feeding practices are associated with young girls' negative self-evaluation of eating.

OBJECTIVE: This study was conducted to determine whether parents' restriction of young girls' access to palatable foods promotes the consumption of those foods while evoking negative self-evaluation. DESIGN: Girls' intake of 10 snack foods was measured immediately following a standard lunch, in a setting with free access to palatable snack foods. Girls' self-evaluation about their eating was assessed following the free access snack session. In addition, reports of parental restriction were obtained from mothers, fathers, and girls. PARTICIPANTS: Participants were 197 girls aged 4.6 to 6.4 years and their parents. STATISTICAL ANALYSIS: Structural equation modeling was used to test models describing relationships between parents' restriction and girls' eating. RESULTS: Following the standard lunch, girls' snack food intake during the 10-minute free access session ranged from 0 to 436 kcal, with a mean of 123 +/- 7 kcal. Approximately half of the girls reported negative self-evaluation about eating 1 or more of the 10 foods provided. The revised path model indicated that parents' restriction predicted both girls' snack food intake and girls' negative self-evaluation of eating. Girls' negative self-evaluation of eating was not associated with the amount of food that they consumed when not hungry, but was linked to their perceptions of being restricted from those foods. APPLICATIONS/CONCLUSIONS: These findings indicate that restricting young girls' access to palatable foods may promote the intake of restricted foods and may also generate negative feelings about eating restricted foods.

Child↗

PubMed1998

Autonomic functions in restrictive cardiomyopathy and constrictive pericarditis: a comparison.

BACKGROUND: This study was undertaken to analyze autonomic functions in restrictive cardiomyopathies. Restrictive cardiomyopathies have clinical and hemodynamic similarity with chronic constrictive pericarditis. Autonomic dysfunction has been described in the latter. METHODS AND RESULTS: Autonomic function analysis has not been reported in restrictive cardiomyopathy. Six consecutive patients with restrictive cardiomyopathy were included in this study (5 men, 1 woman, mean age 35+/-5.4 years). The tests performed were designed to test the sympathetic efferent pathway, that is, by cold hand immersion and loud noise tests, parasympathetic efferent pathway by Valsalva ratio and expiration/inspiration ratio and the baroreceptor function by testing their sensitivity slope. The results were compared with 20 patients with chronic constrictive pericarditis and with 10 healthy age- and sex-matched control subjects previously studied. The rise of systolic blood pressure after cold hand immersion and sudden loud noise was not significantly different compared with control subjects. The expiration/inspiration ratio was 1.1+/-0.01 compared with 1.57+/-0.1 in the control group (p < 0.01). The Valsalva ratio was significantly lower (1.1+/-0.04) compared with control subjects (1.83+/-0.1, p < 0.01). The baroreceptor sensitivity was not reduced compared with that in control subjects. In comparison to constrictive pericarditis, sympathetic efferent pathway is preserved in restrictive cardiomyopathy (p < 0.0001). The parasympathetic efferent pathway is borderline abnormal in restrictive cardiomyopathy but not significantly as compared with constrictive pericarditis (p=not significant). The baroreceptor sensitivity slope is normal in patients with restrictive cardiomyopathy as compared with significant depression seen in constrictive pericarditis (p < 0.05). Autonomic functions are better preserved in patients with restrictive cardiomyopathies compared with chronic constrictive pericarditis. CONCLUSIONS: Autonomic dysfunction is localized to parasympathetic efferent pathway. This is in comparison to constrictive pericarditis, in which severe autonomic dysfunction is a universal feature and includes all segments of autonomic nervous system.

Adolescent↗

PubMed2000

Restricted 12p amplification and RAS mutation in human germ cell tumors of the adult testis.

Human testicular germ-cell tumors of young adults (TGCTs), both seminomas and nonseminomas, are characterized by 12p overrepresentation, mostly as isochromosomes, of which the biological and clinical significance is still unclear. A limited number of TGCTs has been identified with an additional high-level amplification of a restricted region of 12p including the K-RAS proto-oncogene. Here we show that the incidence of these restricted 12p amplifications is approximately 8% in primary TGCTs. Within a single cell formation of i(12p) and restricted 12p amplification is mutually exclusive. The borders of the amplicons cluster in short regions, and the amplicon was never found in the adjacent carcinoma in situ cells. Seminomas with the restricted 12p amplification virtually lacked apoptosis and the tumor cells showed prolonged in vitro survival like seminoma cells with a mutated RAS gene. However, no differences in proliferation index between these different groups of seminomas were found. Although patients with a seminoma containing a homogeneous restricted 12p amplification presented at a significantly younger age than those lacking it, the presence of a restricted 12p amplification/RAS mutation did not predict the stage of the disease at clinical presentation and the treatment response of primary seminomas. In 55 primary and metastatic tumors from 44 different patients who failed cisplatinum-based chemotherapy, the restricted 12p amplification and RAS mutations had the same incidence as in the consecutive series of responding patients. These data support the model that gain of 12p in TGCTs is related to invasive growth. It allows tumor cells, in particular those showing characteristics of early germ cells (ie, the seminoma cells), to survive outside their specific microenvironment. Overexpression of certain genes on 12p probably inhibits apoptosis in these tumor cells. However, the copy numbers of the restricted amplification of 12p and K-RAS mutations do not predict response to therapy and survival of the patients.

Adult↗

PubMed2003

Methionine restriction selectively targets thymidylate synthase in prostate cancer cells.

Tumor cells are more sensitive to methionine restriction than normal tissues, a phenomenon known as methionine auxotrophy. Previous studies showed that 5-fluorouracil and methionine restriction act synergistically against a variety of tumors. The purpose of the current studies was to determine the molecular mechanism(s) underlying this synergy. 5-Fluorouracil is known to inhibit thymidylate synthase (TS), a key enzyme that transfers a methyl group from 5,10-methylene-tetrahydrofolate to dUMP during nucleotide biosynthesis. We found that methionine restriction reduced 5,10-methylene-tetrahydrofolate levels by 75% and selectively inhibited TS activity in PC-3 human prostate cancer cells within 24hr, whereas it did not in normal prostate epithelial cells. The observed fall in TS activity was accompanied by a commensurate reduction in TS protein levels as determined by western blot analysis. In contrast, 5-fluorouracil inhibited TS activity by >90% but increased TS protein levels. This increase was abrogated by methionine restriction. Surprisingly, methionine restriction increased 3H-leucine incorporation in PC-3 cells over the first 24hr, suggesting that reduction of TS levels was not simply due to global protein synthesis inhibition. Methionine restriction also significantly reduced the ratio of dUMP to dTTP in PC-3 cells, creating an imbalanced nucleotide pool. These results suggest that synergy between methionine restriction and 5-fluorouracil is attributable to multiple factors, including depletion of reduced folates, selective inhibition of TS, and creation of an imbalanced nucleotide pool. Dietary and/or enzymatic methionine restriction combined with 5-fluoruracil has great promise as a novel treatment for advanced cancer.

Antimetabolites, Antineoplastic↗

PubMed2002

Caloric restricted male rats demonstrate fewer synapses in layer 2 of sensorimotor cortex.

Previous studies have demonstrated an age-related decline in the density of presumptive inhibitory synapses in layer 2 of rat sensorimotor cortex [J. Comp. Neurol. 439(1) (2001) 65]. Caloric restriction has been shown to ameliorate age-related deterioration in a variety of systems and to extend life span. The present study tested the hypothesis that caloric restriction would prevent the previously reported age-related synaptic decline. Accordingly, synaptic density in layer 2 of sensorimotor cortex was compared between 29-month-old male rats fed ad libitum and 29-month-old male rats that were caloric restricted (60% of ad libitum calories) from 4 months of age. In serial electron micrographs, the physical disector was used to determine the numerical density of presumptive excitatory and inhibitory synapses (those containing round or nonround vesicles, respectively) as well as that of neurons. Not only was the previously reported age-related decline in numerical density of presumptive inhibitory synapses not ameliorated by caloric restriction, the numerical density was significantly lower in caloric restricted than in ad libitum fed rats for total as well as for presumptive excitatory and inhibitory synapses. Analysis further revealed no difference in the numerical density of neurons in this region. Relating synapse density to neuron density as the ratio of synapses to neuron also demonstrated significantly fewer synapses per neuron in caloric restricted than in ad libitum fed old rats. Finally, synapse length was significantly less in caloric restricted rats. These results suggest that not only does caloric restriction fail to prevent the age-related decline in presumptive inhibitory synapses, it results in fewer presumptive excitatory synapses as well.

Aging↗

PubMed1997

Changes in neuropeptide Y immunoreactivity in the arcuate nucleus during and after food restriction in lactating rats.

Previous studies have demonstrated that food restriction during lactation extends the length of lactational infertility in rats. In order to determine whether Neuropeptide Y (NPY) plays a role in the increased length of lactational infertility seen in food-restricted rats, NPY immunoreactivity in the arcuate nucleus of lactating rats that were ad lib fed or food restricted from Day 8 to 14 postpartum was compared. Food-restricted rats showed higher numbers of NPY-stained cells at the end of the food-restriction period (Day 15 postpartum) than did ad lib-fed rats at the same stage of lactation. This difference persisted until Day 25 postpartum although all animals were fed ad libitum from Day 15 onwards. Switching litters between ad lib-fed and food-restricted females from Day 15 until Day 20 postpartum did not eliminate the difference in NPY immunoreactivity between the two diet conditions. Given that food restriction during lactation leads to a prolonged suppression of LH release that also persists after refeeding and is not affected by the nutritional status of the litter, these data are consistent with a role for NPY in the prolonged suppression of reproductive function seen in food restricted lactating rats.

Animals↗

PubMed2002

Augmentation of drug reward by chronic food restriction: behavioral evidence and underlying mechanisms.

Chronic food restriction and maintenance of low body weight have long been known to increase the self-administration and motor-activating effects of abused drugs. Using a lateral hypothalamic self-stimulation (LHSS) rate-frequency method, it is shown that chronic food restriction augments the rewarding (i.e., threshold lowering) effect of diverse drugs of abuse. Further, the effect is attributed to increased sensitivity of a neural substrate, rather than a change in drug bioavailability or pharmacokinetics, because it is preserved when drugs are injected directly into the lateral cerebral ventricle (intracerebroventricularly). The food restriction regimen that augments drug reward also increases the induction of c-fos, by intracerebroventricular amphetamine, in limbic forebrain dopamine (DA) terminal areas. The possibility of increased DA receptor function is suggested by findings that rewarding and motor-activating effects of direct DA receptor agonists are augmented by food restriction, and the augmented behavioral effects of amphetamine are reversed by an otherwise subthreshold dose of D-1 antagonist. Initial studies of DA receptor-mediated signal transduction, that are focused on the D-2 receptor, suggest increased functional coupling between receptor and G-protein (i.e., quinpirole-stimulated [(35)S]GTPgammaS binding) in dorsal striatum. Unlike behavioral sensitization induced by intermittent stress or psychostimulant treatment, which persist indefinitely following induction, the augmenting effect of food restriction abates within 1 week of restored ad libitum feeding and weight gain. The possible involvement of endocrine hormones and/or 'feeding-related' neuropeptides, whose levels change dynamically with depletion and repletion of adipose stores, is therefore under investigation. Initial tests have been limited to acute treatments aimed at attenuating the effects of hypoinsulinemia, hypoleptinemia and elevated corticosterone levels in food-restricted rats. None of these treatments has attenuated the behavioral effect of food restriction. While a melanocortin receptor agonist has been found to enhance drug reward, melanocortin receptors do not seem to mediate the augmenting effect of food restriction. Continuing investigations of endocrine adiposity signals, 'feeding-related' neuropeptides and dopaminergic signal transduction may further elucidate the way in which drugs of abuse exploit mechanisms that mediate survival-related behavior, and help explain the high comorbidity of drug abuse and eating disorders.

Animals↗

PubMed1998

CD1-restricted T-cells influence IgG subclass and IgE production.

BACKGROUND: Human CD1 has recently emerged as a third family of antigen-presenting molecules that is distinct from either major histocompatibility complex class I or class II. OBJECTIVE: We investigated whether the CD1b-restricted T-cell interaction with antigen alters human IgG subclass and IgE isotype production. METHODS: CD1b-restricted antigen-specific T cells derived from the skin lesion of a patient with leprosy were stimulated with their cognate antigen, lipoarabinomman (LAM) of Mycobacterium leprae, in the presence of CD1+ antigen-presenting cells and tested for their ability to alter IgG subclass and IgE production from IgD+ B cells. RESULTS: CD1-restricted T cells cultured with CD1+ antigen-presenting cells in the absence of LAM induced IgG1, IgG3, IgG4, and IgE, whereas CD1b-restricted T cells cultured in the presence of LAM induced IgG1 and IgG3 and inhibited production of IgG4 and IgE. Production of IgG4 and IgE was rescued in the CD1-restricted system by the addition of anti-interferon-gamma. IgG2 production was not induced under any circumstances. CONCLUSION: In this study we demonstrated that a specific CD1b-restricted T-cell line can behave similarly to classically-restricted Th1-type T cells. CD1b-restricted T-cells of this type may regulate immune responses to microbial pathogens by simultaneously enhancing cell-mediated immunity and downregulating IgG4 and IgE responses.

Antigen-Presenting Cells↗

PubMed1998

Early age at repair prevents restrictive right ventricular (RV) physiology after surgery for tetralogy of Fallot (TOF): diastolic RV function after TOF repair in infancy.

OBJECTIVES: To assess diastolic right ventricular (RV) physiology after tetralogy of Fallot repair in infancy. BACKGROUND: Restrictive RV physiology after tetralogy of Fallot repair is related to type of repair, pulmonary regurgitation, and late arrhythmias. METHODS: Forty-seven patients were investigated, 27 and 20 patients in Lund and London, respectively. Median age at repair was 0.78 years (0.08-0.99) and median follow-up was 3.0 years (0.08-10.4). Restrictive RV physiology was assessed by Doppler echocardiography. RESULTS: Thirteen patients (28%) had restrictive RV physiology at follow-up, three of 19 patients (16%) with transatrial repair and 10 of 28 patients (32%) with transventricular repair, respectively (p=0.1). Ten percent of the patients repaired before 6 months of age were restrictive at follow-up, increasing to 38% with repair after 9 months. Transannular patch (TAP) repair was performed in 55% of the patients, including eight of 10 patients (80%) with repair before 6 months of age. Thirty-one percent of the patients with TAP repair were restrictive. These restrictive patients had more severe preoperative pulmonary stenosis (p < 0.05), were older at repair (p < 0.05), and had shorter duration of pulmonary regurgitation (p < 0.001) at follow-up. CONCLUSIONS: Restrictive RV physiology is inversely related to age at repair and independent of type of outflow tract repair. Since TAP repair is more common in early repair, and restriction seems to be less frequent, long-term follow-up to assess adverse effects of pulmonary regurgitation is mandatory.

Age Factors↗

PubMed2000

Effects of a single day of feed restriction on changes in serum leptin, gonadotropins, prolactin, and metabolites in aged and young mares.

In a variety of species, short-term feed restriction leads to rapid changes in the reproductive axis and reduces serum levels of leptin. Two experiments were performed to test the hypothesis that a single day of feed restriction in aged and young mares would cause a suppression of the gonadotropins and serum leptin concentrations. The estrous cycles of 12 aged (>eight years; Exp. 1) and eight young (<five years; Exp. 2) mares were synchronized and the mares were conditioned to twice-daily meal feeding. On the seventh day after synchronization, restricted mares (n = 6 for Exp. 1; n = 4 for Exp. 2) were not fed for 24 hr; all mares were fed the second day. In Exp. 1, serum leptin concentrations significantly decreased in restricted mares, but not in controls. In Exp. 2, serum leptin concentrations declined in restricted mares and no decline was seen in the controls. Serum glucose concentrations did not change in response to feed restriction or refeeding, but in both experiments feed restriction caused an increase in free fatty acids. For both experiments, prolactin, FSH, and LH serum concentrations were not significantly altered by feed restriction. The observed absence of suppression may reflect the maintenance of sufficient levels of metabolizable fuels, rather than a failure of leptin to signal nutritional status to the reproductive axis of the mare.

Aging↗

PubMed2001

The influence of restricted calorie intake on peritoneal macrophage function.

Malnutrition leads to immune dysfunction with greatly increased morbidity. However, restrictive dietary regimens are also known to preserve immune function in autoimmune-susceptible mice. The macrophage (Mø) is central to both immune effector and autoregulatory functions and is critical to host-defense mechanisms. The aim of this study was to investigate the effect of calorie restriction on Mø functions in mice. Female, 6- to 8-wk-old, Swiss Webster mice were randomized to ad libitum feeding for 7 or 21 d (n = 10 mice/group), restricted feeding (13.5 to 14.0 g/cage/d; n = 10) for 7 d, or restricted feeding (16.5 to 17.0 g/cage/d; n = 10) for 21 d. These restrictions were equivalent to a decrease in calorie intake of 21.9% and 5.1%, respectively, over 7 and 21 d. All mice were allowed free access to water. On days 8 and 22, respectively, the mice were killed, and peritoneal Møs were isolated by lavage and adhered to 96-well polystyrene tissue-culture-treated plates. After stimulation with lipopolysaccharide, supernatant prostaglandin E2 and interleukin-6 levels were measured by enzyme-linked immunosorbent assay. Supernatant NO2- in response to stimulation with lipopolysaccharide and interferon-gamma was determined by the Greiss reaction. Prostaglandin E2 production was significantly elevated in peritoneal Møs from the calorie-restricted mice compared with the ad-libitum-fed mice after 7 d. After 21 d, production of both prostaglandin E2 and nitric oxide was significantly increased (P < 0.05) in peritoneal Møs from the restricted mice compared with the ad-libitum-fed mice. These results indicate that calorie restriction influences immune function by altering prostaglandin E2 and nitric oxide generation by Møs.

Animals↗

PubMed2001

Effects of water and feed restriction on body weight change and nitrogen balance in desert goats fed high and low quality forages.

The effects of water and food restriction on feed utilization, body weight changes and nitrogen balance were investigated in Sudanese desert goats given high or low quality forage. Nine male goats were employed in a 3x3 Latin square design where they were subjected to three treatments: ad libitum water and feed, ad-libitum feed/restricted water, and ad libitum water/restricted feed. These treatments were repeated using lucerne or sorghum hay. For both feed types dry matter intake (DMI) was not affected by treatments. Water intake decreased with feed restriction in goats fed sorghum hay. The ratio of water intake to DMI increased with lucerne hay compared to sorghum hay in both the control and feed restricted group. Water consumption increased with lucerne compared to sorghum hay. Body weight losses were more pronounced with water than with feed restriction but were less severe with lucerne than sorghum hay. Interactions due to treatment and feed type were significant for water intake and body weight change. With lucerne hay, except for crude protein (CP), nutrient digestibility improved with water restriction. Feeding sorghum hay, there were no effects on digestibility except for crude protein (CP) that was reduced with water restriction. Crude fiber (CF) and nitrogen free extract (NFE) digestibility increased with feed restriction in animals on sorghum hay. For all groups, CP digestibility was better with lucerne than sorghum hay. Interactions of the main effects were significant for all apparent digestibility coefficients as well as total digestible nutrients. The treatments did not have significant effects on nitrogen balance, however, nitrogen intake, retained or excreted in faeces was higher with lucerne than sorghum hay. It may be concluded that subjecting animals to water or feed restriction will have a more deleterious effect on feed utilization and nitrogen balance when using a low than a high quality forage.

Journal Article↗

PubMed2004

Thermoregulation and water balance as affected by water and food restrictions in Sudanese desert goats fed good-quality and poor-quality diets.

Nine desert goats were used in a 3 x 3 Latin square design in which they were subjected to (a) ad libitum water and food (control), (b) ad libitum food and water restricted to about 40% of the control, and (c) ad libitum water and restricted food (same amount as given to group b). Parameters measured were dry matter intake (DMI), water intake, rectal temperature (Tr), respiration rate (RR), water balance and body weight (BW) changes. The acute effects of the above treatments on these parameters were monitored during the dry summer using two types of feed. The ratio of DMI to water intake decreased (p < 0.01) due to water restriction but increased (p < 0.01) with Lucerne hay compared to grass hay. With both feeds, BW decreased (p < 0.01) with water restriction, with a further decrease (p < 0.01) observed with food restriction. The control group showed a higher (p < 0.01) gain with Lucerne hay than grass hay. Tr and RR increased (p < 0.01) from morning to afternoon; Tr decreased due to food restriction during both morning and afternoon with Lucerne hay (p < 0.05) and grass hay (p < 0.05), whereas RR decreased (p < 0.01) with both types of feeds. For all groups of animals, Tr was higher (p < 0.05) with Lucerne hay than with grass hay, this effect being more pronounced (p < 0.01) with the control group. With both feeds, water restriction decreased (p < 0.01) water turnover rate and evaporative losses, with decreased (p < 0.05) faecal losses observed in the water-restricted groups on Lucerne hay but higher (p < 0.05) losses of urine. The tolerance of desert goats to thermal stress and their coping with shortage of water and food depended on their capacity to lose heat through panting and cutenaous evaporation as well as their ability to concentrate urine.

Adaptation, Physiological↗

PubMed2001

Food restriction affects the gonadotropin releasing hormone neuronal system of male prairie voles (Microtus ochrogaster).

Individuals of species inhabiting temperate and boreal latitudes optimize the timing of energetically costly processes by curtailing nonessential energetically demanding processes when environmental conditions are not favourable. One proximate environmental variable used to fine-tune moment-to-moment changes in reproductive physiology and behaviour is food intake. The neuroendocrine mechanisms by which food restriction leads to the cessation of reproduction in seasonally breeding rodent species remain largely unspecified. The present study sought to determine the effects of extended food restriction on the gonadotropin releasing hormone (GnRH) neuronal system. Male prairie voles (Microtus ochrogaster) were either fed ad libitum or were exposed to either 1, 2 or 3 weeks of moderate (70% of daily mean) food restriction. In accordance with previous studies of food restriction, gross reproductive organ masses and body mass were unaffected by food deprivation. Although 1 week of food restriction did not result in alterations in the GnRH neuronal system, food restriction for 2 weeks was associated with increased GnRH-immunoreactive (GnRH-ir) neurone soma size. Three weeks of food restriction resulted in a pronounced increase in GnRH-ir neurone numbers, as well as an increase in fibre intensity in the main fibre pathway to the median eminence. Taken together, these findings suggest that extended food restriction leads to modifications in the GnRH neuronal system, providing a means for temporary cessation of reproduction without gross alterations in reproductive physiology. This transient change in the hypothalmo-pituitary-gonadal axis, without pronounced changes in reproductive organ morphology, likely provides a mechanism for the rapid reinitiation of breeding in nature when local conditions provide adequate food availability.

Adipose Tissue↗